Although in adults it is usually an acute, self-limited, benign illness, Coxsackie viral myocarditis can pursue a subacute or chronic course leading to permanent cardiac dysfunction or death. Such was the case in a man we studied. Coxsackie B-1 myocarditis, documented by serological tests, had an unusuallly virulent course, causing profound CHF and widespread myocardial destruction in our patient. The non-cardiac organs and tissue, including skeletal muscle, were not involved by the inflammatory process. An unusual feature was extensive transmural scarring of the walls of both ventricles and this resulted in segmental wall motion abnormalities. Studies in experimental models have documented CHF as a complication of viral myocarditis and suggest a possible role of viruses in the pathogenesis of idiopathic dilated cardiomyopathy. Transmural right and left ventricular scarring is rare in patients with idiopathic dilated cardiomyopathy. In 1 reported patient, a 62-year-old woman with symptoms of cardiac dysfunction from dilated cardiomyopathy for 9 years, necropsy disclosed cardiac findings nearly identical to those in the patient described herein, except that inflammatory cells were absent in the scarred myocardium.